Such a method is described e.g. in WO, 01/17268, A1. In this method, for each bit plane, the significant bits, i.e. bits for values, which have had set bits in more significant bit planes are sent first. Then a scan zone is checked for newly significant bits, i.e. set bits outside the group of significant bits, and these bits are included in the bit stream. This provides a reliable and efficient encoding of information blocks, when used for compression of image data. A drawback with this method is that its realisation is quite complex.